Recovering Metal Values from a Metalliferrous Material

ABSTRACT

A method of treating a metalliferrous material source is provided. The metalliferrous material source includes at least one of nickel sulphide and cobalt sulphide, and also includes iron sulphide. The metalliferrous material source is leached with a preliminary leachant in a leaching zone to effect production of a preliminary leach product including a preliminary leach solution and a preliminary leach solid residue. The preliminary leachant includes an aqueous solution comprising ammonia and ammonium sulphate. The preliminary leach solution includes at least one of dissolved nickel comprising material and dissolved cobalt comprising material. The preliminary leach solid residue includes: (i) at least one of nickel sulphide and cobalt sulphide, (ii) at least one of other nickel comprising material and other cobalt comprising material, and (iii) other iron comprising material. At least a fraction of the preliminary leach solid residue is separated from the preliminary leach product such that a metalliferrous material is provided, wherein the metalliferrous material includes at least a fraction of the separated preliminary leach solid residue. At least a fraction of the metalliferrous material is leached with an aqueous solution including dissolved sulphuric acid and dissolved sulphur dioxide in a leaching zone so as to effect production of an operative leach product including a leachate component and a solid residue component, wherein the leachate component includes nickel sulphate, cobalt sulphate, and iron sulphate, and wherein the solid residue component includes at least one of nickel sulphide and cobalt sulphide. At least a fraction of the solid residue component is separated from the operative leach product to provide a recovered solid residue component. The recovered solid residue component is recycled to the preliminary leaching zone.

CROSS-REFERENCE TO RELATED APPLICATIONS

The subject matter of the present application is related to U.S. Application No. ______ (Attorney docket number 15413400) filed on May 27, 2009 and entitled “Recovering Metal Values From a Leach Residue,” which is incorporated by reference herein in its entirety.

FIELD OF THE INVENTION

This invention relates to the recovery of metal values from a metalliferrous material.

BACKGROUND OF THE INVENTION

Pressure leaching of sulphidic concentrates produces residues which often contain valuable minerals whose recovery is interfered with by the fact that such valuable minerals co-precipitate with non-valuable minerals or become occluded within gangue. These residues also include unleached materials, which also contain valuable minerals, and which are commingled with the residues.

SUMMARY OF THE INVENTION

In one aspect, there is provided a method of treating a metalliferrous material source. The method includes providing a metalliferrous material source, wherein the metalliferrous material source includes at least one metalliferrous material source-based target elemental metal and at least one metalliferrous material source-based non-target elemental metal. A process feed material is provided, wherein the process feed material includes the metalliferrous material source. The process feed material is leached in a preliminary leaching zone to effect production of a preliminary leach product including a preliminary leach solution and a preliminary leach solid residue, wherein the preliminary leach solution includes at least one preliminary leach solution-based target elemental metal, and each one of the at least one preliminary leach solution-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal. At least a fraction of the preliminary leach solid residue is separated from the preliminary leach product such that a metalliferrous material is provided, wherein the metalliferrous material is includes at least a fraction of the separated preliminary leach solid residue, and wherein the metalliferrous material includes at least one metalliferrous material-based target elemental metal and at least one metalliferrous material-based non-target elemental metal, wherein each one of the at least one metalliferrous material-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal and at least one of the at least one metalliferrous material-based non-target elemental metal is a one of the at least one metalliferrous material source-based non-target elemental metal. The metalliferrous material is leached with an operative leachant to effect production of an intermediate product mixture including an intermediate operative solution product and an intermediate solid residue, wherein the intermediate operative solution product includes at least one dissolved intermediate operative solution product-based target elemental metal, wherein each one of the at least one dissolved intermediate operative solution product-based target elemental metal is a one of the at least one metalliferrous material-based target elemental metal, and wherein the intermediate solid residue includes at least one intermediate solid residue-based target elemental metal comprising solid material, wherein each one of the at least one intermediate solid residue-based target elemental metal comprising solid material includes at least one intermediate solid residue-based target elemental metal, and wherein each one intermediate solid residue-based target elemental metal is a one of the at least one metalliferrous material-based target elemental metal. At least a fraction of the intermediate solid residue is separated from the intermediate product mixture to provide a separated intermediate solid residue. The separated intermediate solid residue is recycled to the preliminary leaching zone such that the process feed material includes the recycled intermediate solid residue.

In another aspect, there is provided a method of treating a metalliferrous material source. The method includes providing a metalliferrous material source including at least one target elemental metal comprising metalliferrous material source-based metal sulphide and at least one non-target elemental metal comprising metalliferrous material source-based metal sulphide, wherein each one of the at least one target elemental metal comprising metalliferrous material source-based metal sulphide includes at least one metalliferrous material source-based target elemental metal, wherein the at least one target elemental metal comprising metalliferrous material source-based metal sulphide includes at least one of nickel sulphide and cobalt sulphide, such that the at least one metalliferrous material source-based target elemental metal includes at least one of nickel and cobalt, and wherein each one of the at least one non-target elemental metal comprising metalliferrous material source-based metal sulphide includes at least one metalliferrous material source-based non-target elemental metal, wherein the at least one non-target elemental metal comprising metalliferrous material source-based metal sulphide includes iron sulphide, such that the at least one metalliferrous material source-based non-target elemental metal includes iron. A process feed material is provided, wherein the process feed material includes the metalliferrous material source. The process feed material is leached in a preliminary leaching zone with a preliminary leachant to effect production of a preliminary leach product including a preliminary leach solution and a preliminary leach solid residue, wherein the preliminary leach solution includes at least one preliminary leach solution-based target elemental metal, wherein each one of the at least one preliminary leach solution-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal, and wherein the preliminary leach solid residue includes: (i) at least one of nickel sulphide and cobalt sulphide, (ii) at least one of other nickel comprising material and other cobalt comprising material, and (iii) iron comprising material, and wherein the preliminary leachant is an aqueous solution comprising ammonia and ammonium sulphate. At least a fraction of the preliminary leach solid residue is separated from the preliminary leach product such that a metalliferrous material is provided, wherein the metalliferrous material includes at least a fraction of the separated preliminary leach solid residue. At least a fraction of the metalliferrous material is leached with an aqueous solution including dissolved sulphuric acid and dissolved sulphur dioxide in a leaching zone so as to effect production of an operative leach product including a leachate component and a solid residue component, wherein the leachate component includes nickel sulphate, cobalt sulphate, and iron sulphate, and wherein the solid residue component includes at least one of nickel sulphide and cobalt sulphide. At least a fraction of the solid residue component is separated from the operative leach product to provide a recovered solid residue component. The recovered solid residue component is recycled to the preliminary leaching zone.

In another aspect, there is provided a method of treating a metalliferrous material source. The method includes providing a metalliferrous material source including at least one of nickel sulphide and cobalt sulphide, and also including iron sulphide. The metalliferrous material source is leached with a preliminary leachant in a leaching zone to effect production of a preliminary leach product including a preliminary leach solution and a preliminary leach solid residue, wherein the preliminary leachant includes an aqueous solution comprising ammonia and ammonium sulphate, and wherein the preliminary leach solution includes at least one of dissolved nickel comprising material and dissolved cobalt comprising material, and wherein the preliminary leach solid residue includes: (i) at least one of nickel sulphide and cobalt sulphide, (ii) at least one of other nickel comprising material and other cobalt comprising material, and (iii) other iron comprising material. Separating at least a fraction of the preliminary leach solid residue from the preliminary leach product such that a metalliferrous material is provided, wherein the metalliferrous material includes at least a fraction of the separated preliminary leach solid residue. At least a fraction of the metalliferrous material is leached with an aqueous solution including dissolved sulphuric acid and dissolved sulphur dioxide in a leaching zone so as to effect production of an operative leach product including a leachate component and a solid residue component, wherein the leachate component includes nickel sulphate, cobalt sulphate, and iron sulphate, and wherein the solid residue component includes at least one of nickel sulphide and cobalt sulphide. At least a fraction of the solid residue component is separated from the operative leach product to provide a recovered solid residue component. The recovered solid residue component is recycled to the preliminary leaching zone.

BRIEF DESCRIPTION OF DRAWINGS

The system and method of the preferred embodiments of the invention will now be described with the following accompanying drawings:

FIG. 1 is a schematic illustration of the experimental set-up of the H₂SO₄/SO₂ leach step for Example Nos. 1 and 2;

FIG. 2 is a tabular summary of an assay of the feed residue, leach residue, and leach solution in Example No. 1;

FIG. 3 is a schematic illustration of the experimental set-up of the air/ammonia precipitation of iron step for Example Nos. 1 and 2;

FIG. 4 is a tabular summary of assays of reaction solutions, collected at regular intervals from the reactor, and final residue from the air/ammonia precipitation of iron step in Example No. 1;

FIG. 5 is a tabular summary of assay results of solids from oxygen/ammonia leach of residue from H₂SO₄/SO₂ leach of lamellae thickener underflow residue in Example No. 1;

FIG. 6 is a x-ray diffraction analysis of the residue from the ammonia leach of residue from the H₂SO₄/SO₂ leach of lamellae thickener underflow residue in Example No. 1;

FIG. 7 is an x-ray diffraction analysis of an exemplary metalliferrous material, illustrating its composition;

FIGS. 8, 9 and 10 are flowsheets of exemplary embodiments of the invention;

FIGS. 11 and 12 are x-ray diffraction analyses of exemplary solid residues formed after contacting the intermediate operative solution (the leachate from the reductive leach) with aqueous ammonia solution;

FIG. 13 is a tabular summary of the experimental results for the treatment of a relatively low metal sulphide concentration-comprising metalliferrous material feed in Example No. 2;

FIG. 14 is a tabular summary of the experimental results for the treatment of a relatively high metal sulphide concentration-comprising metalliferrous material feed in Example No. 2; and

FIG. 15 is a tabular summary of assays from various steps in the treatment of a relatively low metal sulphide concentration-comprising metalliferrous material feed in Example No. 2.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

There is provided a method 10 of recovering at least one target elemental metal from a metalliferrous material source. Flowsheets illustrating exemplary embodiments of this method are provided as FIGS. 8, 9 and 10.

(A) Providing a Metalliferous Material Source and Leaching a Process Feed Material Including the Metalliferrous Material Source

There is provided a metalliferrous material source. The metalliferrous material source includes at least one metalliferrous material source-based target elemental metal and at least one metalliferrous material source-based non-target elemental metal. For example, the metalliferrous material source is an ore, a concentrate, or any other metal-comprising material.

For example, the metalliferrous material source is a sulphide concentrate. For example, the metalliferrous material source in the form of a sulphide concentrate includes between 35 weight % to 55 weight % nickel, based on the total weight of the metalliferrous material source, and between 1 weight % and 15 weight % cobalt, based on the total weight of the metalliferrous material source, and between 1 weight % and 2.5 weight % iron, based on the total weight of the metalliferrous material source. As a further example, the metalliferrous material source in the form of a sulphide concentrate includes between 52 weight % to 55 weight % nickel, based on the total weight of the metalliferrous material source, and between 6.8 weight % and 7.3 weight % cobalt, based on the total weight of the metalliferrous material source, and between 1.3 weight % and 1.5 weight % iron, based on the total weight of the metalliferrous material source. In some embodiments, the metallifferous material source also includes between 1.5 weight % to 2 weight % zinc, based on the total weight of the metalliferrous material source, and between 0.1 weight % and 0.4 weight % copper, based on the total weight of the metalliferrous material source, and between 0.15 weight % and 0.25 weight % calcium, based on the total weight of the metalliferrous material source, and between 0.1 weight % and 0.2 weight % silicon, based on the total weight of the metalliferrous material source.

For example, with further respect to the metalliferrous material source, the metalliferrous material source includes nickel, cobalt, and iron, wherein each of nickel and cobalt is a metallifferous material source-based target elemental metal, and wherein iron is a metallifferous material source-based non-target elemental metal. The ratio of moles of nickel to moles of iron within the metalliferrous material source is between 21.8 and 66.5. For example, the ratio of moles of nickel to moles of iron within the metalliferrous material source is between 36.7 and 55.6. As a further example, the ratio of moles of nickel to moles of iron within the metalliferrous material source is 44.2. The ratio of moles of cobalt to moles of iron within the metalliferrous material source is between 2.50 and 7.07. For example, the ratio of moles of cobalt to moles of iron within the metalliferrous material source is between 4.03 and 5.55. For example, the ratio of moles of cobalt to moles of iron within the metalliferrous material source is 4.79.

For example, the metalliferrous material source is conditioned such that any one of several characteristics of the metalliferrous material source is modified to improve the suitability of the metalliferrous material source for the leaching. Exemplary characteristics which could be modified include particle size and composition.

For example, the metalliferrous material source is a metalliferrous material source particulate material, and the particle size of the metalliferrous material source particulate material is characterized by an average D50 of 44 microns, as measured with a Horiba™ Analyzer. The surface area of the metalliferrous material source particulate material is characterized by an average surface area of 2320 cm²/cm³, measured with a Horiba^(TM) Analyzer. For example, this average surface area is greater than 2400 cm²/cm³.

For example, the metalliferrous material source includes 55 weight % nickel, based on the total weight of the metalliferrous material source, and includes 6 weight % cobalt, based on the total weight of the metalliferrous material source, and includes 1 weight % iron, based on the total weight of the metalliferrous material source, and the metalliferrous material source is characterized by an average D50 of 60 microns, as measured with a Horiba™ Analyzer.

There is provided a process feed material 100 including the metalliferrous material source. The process feed material 100 is leached with a preliminary treatment leachant in a preliminary leaching zone 10 to effect production of a preliminary operative product 102 including a preliminary operative solution and a preliminary operative solid residue. The preliminary operative solution includes at least one dissolved preliminary operative solution-based target elemental metal, wherein at least one of the at least one dissolved preliminary operative solution-based target elemental metal is a one of the at least one precursor metalliferrous material source-based target elemental metal. At least a fraction of the preliminary operative residue is separated from the product to provide a separated preliminary operative solid residue. At least a fraction of the preliminary operative solution is separated from the preliminary operative product 102 to provide a product leachate 120 including the at least one dissolved preliminary operative solution-based target elemental metal. The product leachate 120 is then, in some embodiments, subjected to further treatment in a target metal recovery unit operation 22 to effect recovery of one or more target metals. For example, suitable processes for some embodiments of leaching of the process feed material are described in U.S. Pat. No. 2,576,314.

In some embodiments, the process feed material 100, including the metalliferrous material source, is leached with a leachant, wherein the leachant is an aqueous solution including 130 g/L of ammonia and 175 g/L ammonium sulphate. For example, the leaching is effected in the preliminary leaching zone 10, wherein the temperature of the preliminary leaching zone is between 240° F. and 250° F., and the pressure within the preliminary leaching zone 10 is between 725 to 900 kPa.

A metalliferrous material 104 is provided, and the metalliferrous material 104 includes at least a fraction of the separated preliminary operative solid residue. The metalliferrous material 104 includes at least one metalliferrous material-based target elemental metal and at least one metalliferrous material-based non-target elemental metal. Each one of the at least one metalliferrous material-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal and is derived from the metalliferrous material source, and at least one of the at least one metalliferrous material-based non-target elemental metal is a one of the at least one metalliferrous material source-based non-target elemental metal and is derived from the metalliferrous material source.

For example, at least a fraction of the metalliferrous material 104 is an agglomerate and at least one of the at least one metalliferrous material-based target elemental metal is occluded within the agglomerate.

For example, the at least one metalliferrous material-based target elemental metal includes at least one of nickel (Ni) or cobalt (Co), and the at least one metalliferrous material-based non-target elemental includes iron (Fe).

In some embodiments, the metalliferrous material 104 includes quantities of nickel, cobalt and iron. In such cases, for example, the metalliferrous material 104 includes between 10 weight % to 20 weight % nickel, based on the total weight of the metalliferrous material 104, and between 5 weight % and 10 weight % cobalt, based on the total weight of the metalliferrous material 104, and between 15 weight % and 35 weight % iron, based on the total weight of the metalliferrous material 104. As a further example, the metalliferrous material 104 includes between 11 weight % to 15 weight % nickel, based on the total weight of the metalliferrous material 104, and between 6 weight % and 7 weight % cobalt, based on the total weight of the metalliferrous material 104, and between 25 weight % and 32 weight % iron, based on the total weight of the metalliferrous material 104. For example, at least a fraction of the nickel provided in the metalliferrous material 104 is in the form of nickel sulphide, nickel sulphate and/or nickel ferrite, at least a fraction of the cobalt provided in the metalliferrous material 104 is in the form of at least one of cobalt ferrite, cobalt sulphide, cobalt sulphate, and/or cobalt oxide, and at least a fraction of the iron provided in the metalliferrous material 104 is in the form of goethite. As a further example, with respect to nickel, nickel is occluded within the metalliferrous material 104.

An x-ray diffraction analysis, of an exemplary metalliferrous material 104, illustrating its composition, is provided in FIG. 7.

In some embodiments, each one of the at least one metalliferrous material-based target elemental metal includes a respective molar quantity such that at least one molar quantity of metalliferrous material-based target elemental metal is provided in the metalliferrous material 104, and each one of the at least one metalliferrous material-based non-target elemental metal includes a respective molar quantity such that at least one molar quantity of metalliferrous material-based non-target elemental metal is provided in the metalliferrous material 104. The ratio of the sum of the at least one molar quantity of metalliferrous material-based target elemental metal to the sum of the at least one molar quantity of metalliferrous material-based non-target elemental metal is between 0.3 and 1.2. For example, the ratio is 0.7. In some embodiments, the at least one metalliferrous material-based target elemental metal is one of nickel and cobalt, and the at least one metalliferrous material-based non-target elemental metal is iron. In some embodiments, the at least one metalliferrous material-based target elemental metal is nickel and cobalt, and the at least one metalliferrous material-based non-target elemental metal is iron.

In some embodiments, prior to effecting solubilisation (described in further detail below) of at least a fraction of the metalliferrous material 104, the residue is washed with hot water in a filter to remove excess ammonium sulphate or ammonia. Such removal mitigates co-precipitation of ammonium sulphate with iron to form a ferrous sulphate/ammonium sulphate double salt during filtering of a solid residue from an intermediate product mixture after leaching of the metalliferrous material, as is described below. The filter which effects the filtering provides locations for feeding of the precipitation, and the precipitation may cause blinding of the filter. As well, removal of excess ammonia at this stage serves to reduce the amount of sulphuric acid used for neutralization.

(B) SOLUBILISING OF THE METALLIFERROUS MATERIAL

At least a fraction of the metalliferrous material 104 is solubilised so as to effect production of a solubilisation product. The solubilisation product includes an intermediate operative solution.

The intermediate operative solution includes a solvent component and a solute component. The solute component includes at least one dissolved intermediate operative solution-based target elemental metal comprising material and at least one dissolved intermediate operative solution-based non-target elemental metal comprising material. Each one of the at least one dissolved intermediate operative solution-based target elemental metal comprising material includes at least one intermediate operative solution-based target elemental metal, and each one of the at least one intermediate operative solution-based target elemental metal is a one of the at least one metalliferrous material-based target elemental metal of the metalliferrous material 104 and is derived from the metalliferrous material 104. Each one of the at least one dissolved intermediate operative solution-based non-target elemental metal comprising material includes at least one intermediate operative solution-based non-target elemental metal, and each one of the at least one intermediate operative solution-based non-target elemental metal is a one of the at least one metalliferrous material-based non-target elemental metal of the metalliferrous material 104 and is derived from the metalliferrous material 104. In this respect, the intermediate operative solution includes at least one intermediate operative solution-based target elemental metal and at least one intermediate operative solution-based non-target elemental metal.

For example, a one of the at least one dissolved intermediate operative solution-based target elemental metal comprising material is cobalt (II) sulphate (CoSO₄). As a further example, a one of the at least one dissolved intermediate operative solution-based target elemental metal comprising material is nickel (II) sulphate (NiSO₄). In some embodiments, the at least one dissolved intermediate operative solution-based target elemental metal comprising material includes cobalt (II) sulphate and nickel (II) sulphate. For example, a one of the at least one dissolved intermediate operative solution-based non-target elemental metal comprising material is iron (II) sulphate (FeSO₄). In some embodiments, the intermediate operative solution includes cobalt (II) sulphate, nickel (II) sulphate, and iron (II) sulphate.

For example, the solubilisation of at least a fraction of the metalliferrous material 104 is effected by leaching of the metalliferrous material 104. In this respect, the metalliferrous material 104 is contacted with an operative leachant in an operative leaching zone 14. For example, the operative leachant is an aqueous solution. Contacting of the metalliferrous material 104 with the leachant effects production of a product mixture 106 including the intermediate operative solution and an intermediate solid residue. The intermediate solid residue includes that fraction of the metalliferrous material 104 which is not solvated within the intermediate operative solution after the metalliferrous material 104 has been subjected to the leaching.

In some embodiments, the operative leachant includes at least one reductant. In this respect, the contacting of the metalliferrous material 104 with the operative leachant effects reduction of at least one operative metalliferrous material-based non-target elemental metal such that at least one reduced metalliferrous material-derived non-target elemental metal is provided, and at least one of the at least one reduced metalliferrous material-derived non-target elemental metal is a component of at least one of the at least one dissolved intermediate operative solution-based non-target elemental metal comprising material. Each one of the at least one operative metalliferrous material-based non-target elemental metal is a one of the at least one metalliferrous material-based non-target elemental metal. The contacting of the metalliferrous material 104 with the leachant also effects reduction of at least one operative metalliferrous material-based target elemental metal such that at least one reduced metalliferrous material-derived target elemental metal is provided, and at least one of the at least one reduced metalliferrous material-derived target elemental metal is a component of at least one of the at least one dissolved intermediate operative solution-based target elemental metal comprising material. Each one of the at least one operative metalliferrous material-based target elemental metal is a one of the at least one metalliferrous material-based target elemental metal.

In some embodiments, the metalliferrous material 104 includes an iron-comprising material, and at least one of (i) a cobalt-comprising material, and (ii) a nickel-comprising material, and the metalliferrous material 104 is contacted with an operative leachant, wherein the operative leachant is an aqueous solution including a reductant. For example, in such embodiments, at least a fraction of any nickel-comprising material includes nickel sulphide, and at least a fraction of any cobalt-comprising material includes cobalt sulphide. An example of a suitable operative leachant is an aqueous solution of sulphuric acid and sulphur dioxide.

In some embodiments, the metalliferrous material includes goethite (FeOOH), cobalt (III) oxide (ie. Co₂O₃), and nickel in a form sequestered in a goethite (FeOOH) matrix, and the metalliferrous material 104 is contacted with an aqueous solution of sulphuric acid and sulphur dioxide in the operative leaching zone, and the contacting effects production of at least one target elemental metal comprising material including at least one of cobalt (II) sulphate (ie. CoSO₄) and nickel (II) sulphate (ie. NiSO₄) and at least one non-target elemental metal comprising materials including iron (II) sulphate (ie. FeSO₄). In this respect, the production of cobalt (II) sulphate (ie. CoSO₄), and iron (II) sulphate (ie. FeSO₄), is effected in accordance with the following reactive processes:

Fe₂O₃(s)+SO₂(aq)+H₂SO₄(aq)2FeSO₄(aq)+H₂O   (1)

Co₂O₃(s)+SO₂(aq)+H₂SO₄(aq)2CoSO₄(aq)+H₂O   (1)

With respect to the nickel (II) sulphate (NiSO₄), it is believed that, in some cases, the nickel (II) sulphate is present and occluded within the metalliferrous material, and is then freed from occlusion when the metalliferrous material is solubilised (for example, leached).

For example, with respect to the reaction mechanisms shown above, one (1) mole of sulphur dioxide and one (1) mole of sulphuric acid are required in order to effect the production of two (2) moles of iron sulphate. The same relationship holds true in effecting the production of the cobalt sulphate. The nickel in the metalliferrous material does not require any sulphuric acid or sulphur dioxide as the nickel (II) sulphate is originally present and occluded within the metalliferrous material and is then freed from occlusion upon solubilising (for example, leaching) of the metalliferrous material 104. An excess of acid is required to neutralize any ammonia that is entrained within the metalliferrous material 104 which is being leached. Also, a slight excess of sulphur dioxide is required to compensate for any losses to atmosphere.

For example, with respect to the operative leaching zone 14 in which the above-described contacting is effected, the operative leaching zone 14 is disposed at a temperature of 85 degrees Celsius and atmospheric pressure. It is anticipated that the reactions proceed faster at higher temperatures and pressures.

In some embodiments, the contacting of the metalliferrous material 104 with a leachant effects production of an intermediate product mixture 106 including the intermediate operative solution and an intermediate solid residue. In some embodiments, the filtering of the intermediate solid residue from the intermediate product mixture 106 is effected soon after the leaching is effected so as to mitigate against obstructions effected by post-precipitation of fine material, such as elemental sulphur. For example, with respect to the intermediate solid residue, the composition of the residue includes nickel sulphide, cobalt sulphide, silica, alumina, and iron sulphide.

In some embodiments, at least a fraction of the intermediate solid residue is recovered and recycled such that at least a fraction of the process feed material includes the recycled intermediate solid residue 108. For example, the recovered intermediate solid residue 108 is recycled to the preliminary leaching zone 10. In this respect, at least a fraction of the intermediate solid residue is separated from the intermediate product mixture 106 to provide the recovered intermediate solid residue 108. For example, the separation is effected in at least one solid-liquid separation unit operation 16.

In some embodiments, the intermediate solid residue includes at least one intermediate solid residue-based target elemental metal comprising material, wherein each one of the at least one intermediate solid residue-based target elemental metal includes at least one intermediate solid residue-based target elemental metal, and each one of the at least one intermediate solid residue-based target elemental metal is a one of the at least one metalliferrous material-based target elemental metal and is derived from the metalliferrous material. In such embodiments, at least a fraction of the intermediate solid residue is recovered and recycled such that at least a fraction of the process feed material includes the recycled intermediate solid residue 108, and thereby also includes the at least one intermediate solid residue-based target elemental metal. For example, the recovered intermediate solid residue 108 is recycled to the preliminary leaching zone 10. In this respect, at least a fraction of the intermediate solid residue is separated from the intermediate product mixture 106 to provide the recovered intermediate solid residue. For example, the separation is effected in at least one solid-liquid separation unit operation 16.

In some embodiments, the intermediate solid residue includes at least one intermediate solid residue-based target metal sulphide, and each one of the at least one intermediate solid residue-based target metal sulphide is derived from the metalliferrous material source. In this respect, the metalliferrous material source includes at least one metalliferrous material source-based target metal sulphide, wherein each one of the at least one metalliferrous material source-based target metal sulphide includes a metalliferrous material source metal sulphide-based target elemental metal, wherein the metalliferrous material source metal sulphide-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal. The metalliferrous material source is included in the process feed material 100 which is leached by the preliminary treatment leachant in the preliminary leaching zone 10. As described above, leaching of the process feed material 100 effects production of a preliminary operative product 102 including a preliminary operative solution and preliminary operative solid residue. In some embodiments, the preliminary leach solid residue includes at least one preliminary operative solid residue-based target metal sulphide, wherein each one of the at least one preliminary operative solid residue-based target metal sulphide is a one of the at least one metalliferrous material source-based target metal sulphide and is derived from the metalliferrous material source. Each one of the at least one preliminary operative solid residue-based target metal sulphide includes at least one preliminary operative solid residue target metal sulphide-based target elemental metal, wherein each one of the at least one preliminary operative residue target metal sulphide-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal. At least a fraction of the preliminary operative solid residue is separated from the preliminary operative product by at least one solid-liquid separation unit operation 12. For example, the at least one unit operation is a lamella thickener and filtration, and the separation is effected by the lamella thickener and filtration, in series. The metalliferrous material 104 includes at least a fraction of the separated preliminary operative solid residue. In this respect, the metalliferrous material 104 includes at least one metalliferrous material-based target metal sulphide, wherein each one of the at least one metalliferrous material-based target metal sulphide is a one of the at least one preliminary operative solid residue-based target metal sulphide and is also, therefore, a one of the at least one metalliferrous material source-based target metal sulphide, and is derived from the metalliferrous material source. Each one of the at least one metalliferrous material-based target metal sulphide includes at least one metalliferrous material target metal sulphide-based target elemental metal which is a one of the at least one metalliferrous material-based target elemental metal (and which is also a one of the at least one metalliferrous material source-based target elemental metal). In this respect, each one of the at least one intermediate solid residue-based target metal sulphide includes at least one intermediate solid residue target metal sulphide-based target elemental metal, and each one of the at least one intermediate solid residue target metal sulphide-based target elemental metal is a one of the at least one metalliferrous material target metal sulphide-based target elemental metal. In some of these embodiments, at least one of the at least one intermediate solid residue target metal sulphide-based target elemental metal is the same target elemental metal as a one of the at least one dissolved intermediate operative solution-based target elemental metal. In some of these embodiments, at least one of the at least one intermediate solid residue target metal sulphide-based target elemental metal is a one of the at least one dissolved preliminary operative solution-based target elemental metal (of the product leachate 120). At least a fraction of the intermediate solid residue is recovered and recycled such that at least a fraction of the process feed material includes the recycled intermediate solid residue 108, and thereby also includes the at least one intermediate solid residue-based target metal sulphide. For example, the recovered intermediate solid residue 108 is recycled to the preliminary leaching zone 10. In this respect, at least a fraction of the intermediate solid residue is separated from the intermediate product mixture 106 to provide the recovered intermediate solid residue 108, and also to provide an operation feed 110, including the intermediate operative solution, which is then introduced to the reaction zone 18, as will be described in further detail below. For example, the separation is effected in at least one solid-liquid separation unit operation 16. In some of these embodiments, the at least one intermediate solid residue-based target metal sulphide of the recycled intermediate solid residue is at least one of nickel sulphide and cobalt sulphide.

In some embodiments, the metalliferrous material 104 includes a relatively high concentration of the at least one metalliferrous material based target metal sulphide. In some of these embodiments, this is attributable to a relatively high concentration of the at least one metalliferrous material source-based target metal sulphide, and that an appreciable fraction of the at least one metalliferrous material source-based target metal sulphide of the metalliferrous material source remains unaffected by the leaching of the process feed material 100 in the preliminary leaching zone 10 (in some embodiments, this is referred to as “underleaching”, and is an indication that the leaching zone 10 is being overfed) such that the preliminary leach solid residue whose production is effected by the leaching of the process feed material 100 includes a relatively high concentration of the at least one preliminary leach solid residue-based target metal sulphide, and this translates to a relatively high concentration of the at least one metalliferrous material based target metal sulphide. In those embodiments where the metalliferrous material 104 includes a relatively high concentration of the at least one metalliferrous material based target metal sulphide, the intermediate solid residue whose production is effected by the leaching of the metalliferrous material includes a relatively high concentration of the at least one intermediate solid residue-based target metal sulphide. In such cases, the separation of the at least a fraction of the intermediate solid residue from the intermediate product mixture is effected by at least one solid-liquid separation unit operation 16. For example, the separation is effected by a lamella thickener and filtration, in series. In some of these embodiments, when the metalliferrous material includes silica, the practising of these embodiments may effect an internal recycle of silica and, thereby, effect a build-up of silica which may be undesirable. This may, therefore, require intermittent bleeding of silica from the process or an adjustment to the throughput of the process feed material 100 through the leaching zone 10. FIG. 8 is illustrative of such embodiments. It is understood, however, that this underleaching (or “overfeeding”) scenario is a rare situation, and when it does occur, steps are taken to correct the situation. FIG. 8 is illustrative of the “underleaching” embodiments.

In some embodiments, the metalliferrous material 104 includes an intermediate concentration of the at least one metalliferrous material based target metal sulphide. In some of these embodiments, this is attributable to an intermediate concentration of the at least one metalliferrous material source-based target metal sulphide, and that a fraction, intermediate to the relatively high fraction and the relatively low fraction, of the at least one metalliferrous material source-based target metal sulphide of the metalliferrous material source remains unaffected by the leaching of the process feed material 100 in the preliminary leaching zone 10 such that the preliminary leach solid residue whose production is effected by the leaching of the process feed material 100 includes an intermediate concentration of the at least one preliminary leach solid residue-based target metal sulphide, and this translates to an intermediate concentration of the at least one metalliferrous material based target metal sulphide. In those embodiments where the metalliferrous material 104 includes an intermediate concentration of the at least one metalliferrous material based target metal sulphide, the intermediate solid residue whose production is effected by the leaching of the metalliferrous material 104 includes an intermediate concentration of the at least one intermediate solid residue-based target metal sulphide. In such cases, the at least one unit operation 16 which effects separation of the at least a fraction of the intermediate solid residue from the intermediate product mixture includes flotation 16A. Flotation 16A is used in such cases in order to provide a more concentrated recovered intermediate solid residue fraction 108 for recycle to the preliminary leaching zone 10. The floatation 16A effects production of a floated concentrate 1062 and tailings material 1064. The floated concentrate 1062 includes an intermediate solid residue component and a liquid component. The intermediate solid residue component of the floated concentrate 1062 is at least a fraction of the intermediate solid residue of the intermediate product mixture 106. At least a fraction of the intermediate solid residue component of the floated concentrate 1062 (and, therefore, at least a fraction of the intermediate solid residue of the product mixture 106) is recovered and recycled such that at least a fraction of the process feed material 100 includes the recycled intermediate solid residue 108. In this respect, at least a fraction of the intermediate solid residue component is separated from the floated concentrate 1062 in a solid-liquid separation unit operation 16B (such as a mechanical filtration unit operation) to provide the recovered intermediate solid residue 108, which is then recycled to the preliminary leaching zone 10, and also to provide a filtrate 1066 which is combined with the tailings material 1064 to form the operative feed 110 to the reaction zone 18. FIG. 9 is illustrative of such embodiments.

In some embodiments, the metalliferrous material 104 includes a relatively low concentration of the at least one metalliferrous material based target metal sulphide. In some of these embodiments, this is attributable to a relatively low concentration of the at least one metalliferrous material source-based target metal sulphide, and that an appreciable fraction of the at least one metalliferrous material source-based target metal sulphide of the metalliferrous material source is solubilised by the leaching of the process feed material 100 in the preliminary leaching zone 10 (in some embodiments, this is referred to as “overleaching”, and is an indicator that the leaching zone 10 is being underfed) such that the preliminary leach solid residue whose production is effected by the leaching of the process feed material 100 includes a relatively low concentration of the at least one preliminary leach solid residue-based target metal sulphide, and this translates to a relatively low concentration of the at least one metalliferrous material based target metal sulphide. In those embodiments where the metalliferrous material 104 includes a relatively low concentration of the at least one metalliferrous material based target metal sulphide, the intermediate solid residue whose production is effected by the leaching of the metalliferrous material 104 includes a relatively low concentration of the at least one intermediate solid residue-based target metal sulphide. In some of these cases, it is not economically justifiable to effect separation of the at least a fraction of the intermediate solid residue from the intermediate product mixture and then effect its recycle to the preliminary leaching zone 10. In such cases, the intermediate product mixture 106 is provided as the operative feed 110 to the reaction zone 18 so as to effect contact between the intermediate operative solution and at least one reagent material system, as will be further described below. FIG. 10 is illustrative of such embodiments.

In some embodiments, depending on the relative concentration of the at least one metalliferrous material source-based target metal sulphide, any one of the embodiments of the method illustrated in FIGS. 8, 9, and 10 is selected. In this respect, an indication of the relative concentration of the at least one metalliferrous material source-based target metal sulphide is based upon a combination of a measured concentration of a one of the at least one metalliferrous material-based target elemental metal and a measured concentration of a one of the at least one metalliferrous material-based non-target elemental metal. In this respect, if the concentration of the metalliferrous material-based target elemental metal whose concentration is being measured is greater than a pre-determined value and the concentration of the metalliferrous material-based non-target elemental metal whose concentration is being measured is less that a predetermined value, this is an indication of a relatively high concentration of the metalliferrous material-based target metal sulphide, and an embodiment of the method illustrated in FIG. 8 is selected. If the concentration of the metalliferrous material-based target elemental metal whose concentration is being measured is less than a pre-determined value and the concentration of the metalliferrous material-based non-target elemental metal whose concentration is being measured is greater than a pre-determined value, this is an indication of a relatively low concentration of the at least one metalliferrous material-based target metal sulphide, and an embodiment of the method illustrated in FIG. 10 is selected. Otherwise, an embodiment of the method illustrated in FIG. 9 is selected.

(C) Contacting the Intermediate Operative Solution With an Operative Reagent, and Facilitating Recovery of the Target Elemental Metal

The intermediate operative solution is contacted with reagent material in the reaction zone 18.

In this respect, reagent material is provided in the reaction zone 18. The reagent material includes at least one precipitation agent material and at least one complexing agent material.

Each one of the at least precipitation agent material is configured to react with at least one of the at least one dissolved intermediate operative solution-based elemental metal comprising material when the intermediate operative solution is contacted with the reagent material so as to effect production of at least one solid residue component-based elemental metal comprising solid material. For any reaction of a dissolved intermediate operative solution-based target elemental metal comprising material with a precipitation agent material, there is effected production of at least one solid residue component-based target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based target elemental metal comprising solid material includes at least one solid residue component target elemental metal comprising solid material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component target elemental metal comprising solid material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material. For any reaction of a dissolved intermediate operative solution-based non-target elemental metal comprising material with a precipitation agent material, there is effected production of at least one solid residue component-based non-target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based non-target elemental metal comprising solid material includes at least one solid residue component non-target elemental metal comprising solid material-based non-target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component non-target elemental metal comprising solid material-based non-target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component non-target elemental metal comprising solid material-based non-target elemental metal is a one of the at least one intermediate operative solution-based non-target elemental metal and is derived from the metalliferrous material.

Each one of the at least complexing agent material is configured to react with at least one of the at least one dissolved intermediate operative solution-based elemental comprising material when the intermediate operative solution is contacted with the reagent material so as to effect production of at least one product solution component-based elemental metal comprising dissolved complex material. For any reaction of a dissolved intermediate operative solution-based target elemental metal comprising material with a complexing agent material, there is effected production of at least one product solution component-based target elemental metal comprising dissolved complex material, wherein each one of the at least one product solution component-based target elemental metal comprising dissolved complex material includes at least one product solution component target elemental metal comprising dissolved complex material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one product solution component target elemental metal comprising dissolved complex material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced product solution component target elemental metal comprising dissolved complex material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material. For any reaction of a dissolved intermediate operative solution-based non-target elemental metal comprising material with a complexing agent material, there is effected production of at least one product solution component-based non-target elemental metal comprising dissolved complex material, wherein each one of the at least one product solution component-based non-target elemental metal comprising dissolved complex material includes at least one product solution component non-target elemental metal comprising dissolved complex material-based non-target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one product solution component non-target elemental metal comprising dissolved complex material-based non-target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced product solution component non-target elemental metal comprising dissolved complex material-based non-target elemental metal is a one of the at least one intermediate operative solution-based non-target elemental metal and is derived from the metalliferrous material.

There is also provided at least one operative dissolved intermediate operative solution-based target elemental metal comprising material. The at least one operative dissolved intermediate operative solution-based target elemental metal comprising material is included within the intermediate operative solution such that each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material is a one of the at least one dissolved intermediate operative solution-based target elemental metal comprising material. Each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material is configured to react with at least one of the at least one precipitation agent material, when the intermediate operative solution is contacted with the reagent material, to effect production of at least one solid residue component-based target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based target elemental metal comprising solid material includes at least one solid residue component target elemental metal comprising solid material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component target elemental metal comprising solid material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material. Each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material is also configured to react with at least one of the at least one complexing agent material, when the intermediate operative solution is contacted with the reagent material, to effect production of at least one product solution component-based target elemental metal comprising dissolved complex material, wherein each one of the at least one product solution component-based target elemental metal comprising dissolved complex material includes at least one product solution component target elemental metal comprising dissolved complex material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, and such that at least one product solution component target elemental metal comprising dissolved complex material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced product solution component target elemental metal comprising dissolved complex material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material.

There is also provided at least one operative dissolved intermediate operative solution-based non-target elemental metal comprising material, wherein the at least one operative dissolved intermediate operative solution-based non-target elemental metal comprising material is included within the intermediate operative solution such that each one of the at least one operative dissolved intermediate operative solution-based non-target elemental metal comprising material is a one of the at least one dissolved intermediate operative solution-based non-target elemental metal comprising material. Each one of the at least one operative dissolved intermediate operative solution-based non-target elemental metal comprising material is configured to react at least with at least one of the at least one precipitation agent material, when the intermediate operative solution is contacted with the reagent material, to effect production of at least one solid residue component-based non-target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based non-target elemental metal comprising solid material includes at least one solid residue component non-target elemental metal comprising solid material-based non-target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component non-target elemental metal comprising solid material-based non-target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component non-target elemental metal comprising solid material-based non-target elemental metal is a one of the at least one intermediate operative solution-based non-target elemental metal and is derived from the metalliferrous material.

The intermediate operative solution is contacted with the reagent material in the reaction zone 18, such that production of a product mixture is effected. The product mixture includes a product solution component and a solid residue component. The product solution component includes the at least one produced product solution component target elemental metal comprising dissolved complex material-based target elemental metal and any produced product solution component non-target elemental metal comprising dissolved complex material-based non-target elemental metal. The solid residue component includes the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal and the at least one produced solid residue component non-target elemental metal comprising solid material-based non-target elemental metal.

With respect to the product solution component, there is provided a respective molar quantity of each one of the at least one produced product solution component target elemental metal comprising dissolved complex material-based target elemental metal such that at least one produced product solution component target elemental metal comprising dissolved complex material-based target elemental metal molar quantity is provided. There is also provided a molar quantity of any produced product solution component non-target elemental metal comprising dissolved complex material-based non-target elemental metal. The ratio of (A1) the sum of the at least one produced product solution component target elemental metal comprising dissolved complex material-based target elemental metal molar quantity to (B1) the molar quantity of any produced product solution component non-target elemental metal comprising dissolved complex material-based non-target elemental metal is defined by R1.

With respect to the solid residue component, there is provided a molar quantity of any produced solid residue component target elemental metal comprising solid material-based target elemental metal. There is also provided a respective molar quantity of each one of the at least one produced solid residue component non-target elemental metal comprising solid material-based non-target elemental metal such that at least one produced solid residue component non-target elemental metal comprising solid material-based non-target elemental metal molar quantity is provided. The ratio of (A2) the molar quantity of any produced solid residue component target elemental metal comprising solid material-based target elemental metal to (B2) the sum of the at least one produced solid residue component non-target elemental metal comprising solid material-based non-target elemental metal molar quantity is defined by R2.

R1 is greater than R2. For example, R1/R2 is greater than 1000. As a further example R1/R2 is greater than 100,000. As a further example, R1/R2 is greater than 1,000,000.

In some embodiments, the contacting of the intermediate operative solution with the reagent material in the reaction zone effects,:

-   (i) reaction of each one of the at least one operative dissolved     intermediate operative solution-based non-target elemental metal     comprising material with at least one of the at least one     precipitation agent material to effect production of at least one     solid residue component-based non-target elemental metal comprising     solid material, wherein each one of the at least one solid residue     component-based non-target elemental metal comprising solid material     includes at least one solid residue component non-target elemental     metal comprising solid material-based non-target elemental metal,     wherein at least one reaction is effected when the intermediate     operative solution is contacted with the reagent material, such that     at least one solid residue component non-target elemental metal     comprising solid material-based non-target elemental metal is     produced by the at least one reaction effected when the intermediate     operative solution is contacted with the reagent material, wherein     each one of the at least one produced solid residue component     non-target elemental metal comprising solid material-based     non-target elemental metal is a one of the at least one intermediate     operative solution-based non-target elemental metal and is derived     from the metalliferrous material ; and -   (ii) reaction of each one of the at least one operative dissolved     intermediate operative solution-based target elemental metal     comprising material with at least one of the at least one complexing     agent material to effect production of at least one product solution     component-based target elemental metal comprising dissolved complex     material, wherein each one of the at least one product solution     component-based target elemental metal comprising dissolved complex     material includes at least one product solution component target     elemental metal comprising dissolved complex material-based target     elemental metal, wherein at least one reaction is effected when the     intermediate operative solution is contacted with the reagent     material, such that at least one product solution component target     elemental metal comprising dissolved complex material-based target     elemental metal is produced by the at least one reaction effected     when the intermediate operative solution is contacted with the     reagent material, wherein each one of the at least one produced     product solution component target elemental metal comprising     dissolved complex material-based target elemental metal is a one of     the at least one intermediate operative solution-based target     elemental metal and is derived from the metalliferrous material;     such that the product solution component includes the at least one     produced product solution component-based target elemental metal     comprising dissolved complex material, and the solid residue     component includes the at least one produced solid residue     component-based non-target elemental metal comprising solid     material.

In some embodiments, the contacting of the intermediate operative solution with the reagent material in the reaction zone 18 effects circumstances wherein there is provided a material propensity for each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material to effect reaction with at least one of the at least one precipitation agent material to effect production of at least one solid residue component-based target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based target elemental metal comprising solid material includes at least one solid residue component target elemental metal comprising solid material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component target elemental metal comprising solid material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material

In some embodiments, the contacting of the intermediate operative solution with the reagent material in the reaction zone 18 effects circumstances wherein there is provided a material propensity for each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material to effect reaction with at least one of the at least one precipitation agent material to effect production of at least one solid residue component-based target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based target elemental metal comprising solid material includes at least one solid residue component target elemental metal comprising solid material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component target elemental metal comprising solid material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material, and wherein there exists a material propensity for at least one of the at least one produced solid residue component-based target elemental metal comprising solid material to co-precipitate with at least one of the at least one solid residue component-based non-target elemental metal comprising solid material.

In some embodiments, the contacting of the intermediate operative solution with the reagent material in the reaction zone 18 effects circumstances wherein there is provided a material propensity for each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material to effect reaction with at least one of the at least one precipitation agent material to effect production of at least one solid residue component-based target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based target elemental metal comprising solid material includes at least one solid residue component target elemental metal comprising solid material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component target elemental metal comprising solid material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material. There exists a material propensity for at least a fraction of the at least one solid residue component-based target elemental metal comprising solid material to become occluded within an agglomerate of the solid residue component.

In some embodiments, there is insubstantial propensity for at least one of the at least one at least one operative dissolved intermediate operative solution-based non-target elemental metal comprising material to react with any one of the at least one complexing agent when the intermediate operative solution is contacted with the reagent material. For example, there is insubstantial propensity for each one of the at least one at least one operative dissolved intermediate operative solution-based non-target elemental metal comprising material to react with any one of the at least one complexing agent when the intermediate operative solution is contacted with the reagent material.

In some embodiments, the contacting of the intermediate operative solution with the reagent material in the reaction zone effects reaction of each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material with at least one of the at least one precipitation agent material to effect production of at least one solid residue component-based target elemental metal comprising solid material, wherein each one of the at least one solid residue component-based target elemental metal comprising solid material includes at least one solid residue component target elemental metal comprising solid material-based target elemental metal, wherein at least one reaction is effected when the intermediate operative solution is contacted with the reagent material, such that at least one solid residue component target elemental metal comprising solid material-based target elemental metal is produced by the at least one reaction effected when the intermediate operative solution is contacted with the reagent material. Each one of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal is a one of the at least one intermediate operative solution-based target elemental metal and is derived from the metalliferrous material. In this respect, the solid residue component includes the at least one solid residue component-based target elemental metal comprising solid material. Also, in this respect, there is provided a respective molar quantity of each one of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal such that at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal molar quantity is provided, and wherein the molar quantity of any produced solid residue component target elemental metal comprising solid material-based target elemental is the sum of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal molar quantity, such that the ratio, R2, is defined as the ratio of (A2) the sum of the at least one produced solid residue component target elemental metal comprising solid material-based target elemental metal molar quantity to (B2) the sum of the at least one produced solid residue component non-target elemental metal comprising solid material-based non-target elemental metal molar quantity.

For example, in those embodiments (which are described immediately above) where the contacting of the intermediate operative solution with the reagent material in the reaction zone effects reaction of each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material with at least one of the at least one precipitation agent material to effect production of at least one solid residue component-based target elemental metal comprising solid material, at least one of the at least one produced solid residue component-based target elemental metal comprising solid material is co-precipitated with at least one of the at least one solid residue component-based non-target elemental metal comprising solid material. As a further example, the solid residue component includes the at least one solid residue component-based target elemental metal comprising solid material, and at least a fraction of the solid residue component includes an agglomerate, and at least a fraction of the at least one solid residue component-based target elemental metal comprising solid material is occluded within the agglomerate.

FIGS. 11 and 12 are x-ray diffraction analyses of exemplary solid residue components which are produced after contacting the intermediate operative solution (including dissolved nickel, cobalt, and iron materials) with the at least one reagent system (aqueous ammonia solution).

In some embodiments, with respect to the reagent material, the ratio of (i) moles of the at least one complexing agent material to (ii) moles of the at least one precipitation agent material is controlled above a predetermined value. For example, the ratio of (i) moles of the at least one complexing agent material to (ii) moles of the at least one precipitation agent material is greater than 700.

In some embodiments, there is provided a respective molar quantity of each one of the at least one operative intermediate operative solution-based target elemental metal in the reaction zone such that at least one operative target elemental metal molar quantity is provided in the reaction zone. There is also provided a respective molar quantity of each one of the at least one complexing agent material in the reaction zone such that at least one complexing agent molar quantity is provided in the reaction zone. In the reaction zone, the ratio of (A) the sum of the at least one complexing agent molar quantity to (B) the sum of the at least one operative target elemental metal molar quantity is at least 5:1. For example, the ratio is at least 6:1. As a further example, the ratio is at least 8:1.

In some embodiments, the reagent material is at least one reagent material system, wherein each one of the at least one reagent material system includes a respective at least two material states, wherein a fraction of each one of the at least one reagent material system is disposed in a one of the respective at least two material states and another fraction of each one of the at least one reagent material system is disposed in another one of the respective at least two material states, and wherein, for each one of the at least one reagent material system, the one of the respective at least two material states includes a precipitation agent material and the another one of the respective at least two material states includes a complexing agent material, such that the at least one reagent material system provides at least one precipitation agent material and at least one complexing agent material. For each one of the at least one reagent material system, transformation between the one of the respective at least two material states and the another one of the respective at least two material states is effected in response to a driving force provided for effecting thermodynamic equilibrium between the one of the respective at least two material states and the another one of the respective at least two material states. An example of such a reagent material system is an aqueous ammonia solution. In this respect, the precipitation agent material for a one of the material states of the aqueous ammonia solution is hydroxide ion (OH), and the complexing agent of another one of the material states of the aqueous ammonia solution is ammonia (NH₃).

In some embodiments, the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material is at least one of cobalt (II) sulphate (CoSO₄) and nickel (II) sulphate (NiSO₄). In such embodiments, the at least one operative dissolved intermediate operative solution-based non-target elemental metal comprising material is iron (II) sulphate (FeSO₄). At least a fraction of the intermediate operative solution of such embodiments is contacted with reagent material in a reaction zone. In this respect, for example, the reagent material is aqueous ammonia solution, wherein the complexing agent material is ammonia (NH₃) and the precipitation agent material is hydroxide ion (OH⁻). Ammonia and hydroxide ion are disposed in the following equilibrium in aqueous solution:

NH₃(aq)+H₂O(l)→NH₄ ⁺(aq)+OH⁻(aq)

The contacting effects production of a product mixture including a product solution component and a solid residue component. When an operative dissolved intermediate operative solution-based target elemental metal comprising material in the reaction zone is cobalt (II) sulphate (CoSO₄), the solution product includes Co(NH₃)₆SO₄. When an operative dissolved intermediate operative solution-based target elemental metal comprising material in the reaction zone is (II) sulphate (NiSO₄), the solution product includes Ni(NH₃)₆SO₄. Each one of Co(NH₃)₆SO₄ and Ni(NH₃)₆SO₄ is a product solution component-based target elemental metal comprising dissolved complex material. The reactive processes which effect the production of each one of Co(NH₃)₆SO₄ and Ni(NH₃)₆SO₄ respectively proceed in accordance with the following reactive processes:

CoSO₄(aq)+6NH₃(aq)→Co(NH₃)₆SO₄(aq)

NiSO₄(aq)+6NH₃(aq)→Ni(NH₃)₆SO₄(aq)

With respect to the iron sulphate, in some embodiments, substantially none of the iron forms an ammonia complex when the intermediate operative solution is contacted with reagent material in a reaction zone.

As mentioned above, the contacting also effects production of a solid residue component. The solid residue component includes at least one produced solid residue component-based non-target elemental metal comprising solid material, and, in this case, the at least one produced solid residue component-based non-target elemental metal comprising solid material is ferrous hydroxide (Fe(OH)₂). The reactive process which effects production of ferrous hydroxide (Fe(OH)₂) is as follows:

FeSO₄(aq)+2NH₄OH(aq)→Fe(OH)₂(s)+(NH₄)₂SO₄(aq)

There is also a propensity for each one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material to react with the precipitation agent material to effect production of a solid residue component-based target elemental metal comprising solid material. When an operative dissolved intermediate operative solution-based target elemental metal comprising material in the reaction zone is cobalt (II) sulphate (CoSO₄), the cobalt (II) sulphate includes a propensity to react with the hydroxide ion of the ammonia solution to effect production of a solid residue component-based target elemental metal comprising solid material in the form of cobalt hydroxide (Co(OH)₂), in accordance with the following reactive process:

CoSO₄(aq)+2NH₄OH(aq)→Co(OH)₂(s)+(NH₄)₂SO₄(aq)

When an operative dissolved intermediate operative solution-based target elemental metal comprising material in the reaction zone is nickel (II) sulphate (NiSO₄), the nickel (II) sulphate includes a propensity to react with the hydroxide ion of the ammonia solution to effect production of a solid residue component-based target elemental metal comprising solid material in the form of nickel hydroxide (Ni(OH)₂), in accordance with the following reactive process:

NiSO₄(aq)+2NH₄OH(aq)→Ni(OH)₂(s)+(NH₄)₂SO₄(aq)

In some embodiments, when the at least one solid residue component-based target elemental metal comprising solid material (for example, at least one of cobalt hydroxide and nickel hydroxide) is produced, the at least one solid residue component-based target elemental metal comprising solid material co-precipitates with the solid residue component-based non-target elemental metal comprising solid material (for example, in the form of Fe(OH)₂). Also, in some embodiments, when the at least one solid residue component-based target elemental metal comprising solid material (for example, at least one of cobalt hydroxide and nickel hydroxide) is produced, the at least solid residue component-based target elemental metal comprising solid material is occluded within an agglomerate, wherein the agglomerate primarily comprises the solid residue component-based non-target elemental metal comprising solid material (for example, in the form of Fe(OH)₂). If sufficient concentration of complexing agent material (for example, in this case, ammonia) is provided uniformly throughout the reaction zone, the co-precipitation or the occlusion is at least mitigated. In such cases, even if the solid residue component-based target elemental metal comprising solid material is produced, if there is sufficient ammonia concentration in the immediate vicinity where the solid residue component-based target elemental metal comprising solid material is produced, the solid residue component-based target elemental metal comprising solid material is likely to convert to a respective product solution component-based target elemental metal comprising dissolved complex material before becoming occluded within an agglomerate and before co-precipitating with the iron hydroxide. In order to mitigate against sub-zones (within the reaction zone) of low ammonia concentration, the reaction is subjected to mixing, such as turbulent mixing, so as to facilitate uniformity of sufficient ammonia concentration throughout the reaction zone, and thereby provide conditions whereby any produced solid residue component-based target elemental metal comprising solid material is quickly converted to a product solution component-based target elemental metal comprising dissolved complex material (for example, Co(NH₃)₆SO₄ and/or Ni(NH₃)₆SO₄), before there is an opportunity to occlude the produced solid residue component-based target elemental metal comprising solid material in an agglomerate and before there is an opportunity for the produced solid residue component-based target elemental metal comprising solid material to co-precipitate with the solid residue component-based non-target elemental metal comprising solid material.

In some embodiments, in order to also mitigate against the co-precipitation or occlusion of at least one of the cobalt hydroxide and the nickel hydroxide, the ratio of moles of aqueous ammonia to moles of aqueous hydroxide ion in the reaction zone is controlled above a predetermined value. For example, the ratio of moles of aqueous ammonia to moles of aqueous hydroxide ion is at least 700.

In some embodiments, in order to also mitigate against the co-precipitation or occlusion of at least one of the cobalt hydroxide and the nickel hydroxide, the concentration of aqueous ammonia in the reaction zone is at least 180 grams per litre.

In some embodiments, in order to also mitigate against the co-precipitation or occlusion of at least one of the cobalt hydroxide and the nickel hydroxide, there is provided a respective molar quantity of each one of the at least one intermediate operative solution-based target elemental metal in the reaction zone 18 such that at least one target elemental metal molar quantity is provided in the reaction zone 18 (if cobalt and nickel are the only target metal, then there are two values, and one value is the number of moles of cobalt in the reaction zone, and the second value is the number of moles of nickel in the reaction zone), and the ratio of moles of aqueous ammonia in the reaction zone to the sum of the at least one target elemental metal molar quantity in the reaction zone (if cobalt or nickel is the only target elemental metal, then this value is the number of moles of cobalt or nickel in the reaction zone, and if both cobalt and nickel are target elemental metals, then this value is the sum of the number of moles of cobalt and the number of moles of nickel) is at least 5:1. For example, this ratio is at least 6:1. As a further example, this ratio is at least 8:1.

For example, with respect to the contacting of the intermediate operative solution with the reagent material in the reaction zone 18, the reaction zone 18 is disposed in a reaction vessel, and the reagent material is flowed into the reaction vessel to effect the contacting of the intermediate operative solution with the reagent material in the reaction zone 18. In this manner, the reagent material is replenished within the reaction zone 18 to maintain a pre-determined minimum concentration of ammonia in the reaction zone 18.

For example, after the contacting with the reagent material to effect production of the product mixture 112, the product mixture 112 is then contacted with an operative reagent to react with at least one of the at least one solid residue component-based non-target elemental metal comprising solid material to effect production of a treated product mixture 114 including at least one converted solid residue component-based non-target elemental metal comprising solid material, wherein each one of the at least one converted solid residue component-based non-target elemental metal comprising solid material includes faster settling characteristics relative to the at least one solid residue component-based non-target elemental metal comprising solid material from which the respective one of the at least one converted solid residue component-based non-target elemental metal comprising solid material is derived.

For example, the operative reagent includes oxygen (O₂), and the oxygen reacts with the produced ferrous hydroxide (Fe(OH)₂) to produce ferric oxide (Fe₂O₃) in accordance with the following reaction mechanism:

2Fe(OH)₂(s)+½O₂(aq)→Fe₂O₃(s)+2H₂O(1)

The produced ferric oxide (Fe₂O₃) is, in general, in the form of larger particles than the ferrous hydroxide (Fe(OH)₂) which is subjected to the reactive process to produce the ferric oxide. In this respect, the produced ferric oxide is easier to separate from the intermediate mixture product by mechanical filtration than is the ferrous hydroxide. As well, the ferric oxide is more stable than the ferrous hydroxide in air.

For example, the oxygen is introduced into the reaction zone 18 by flowing a mixture of ammoniated air into the reaction zone 18 of the reaction vessel. For example, the composition of the ammoniated air mixture is sufficient such that ammonia is not significantly depleted within the reaction zone so as to compromise the desired conversion of any one of the at least one operative dissolved intermediate operative solution-based target elemental metal comprising material to a respective at least one product solution component-based target elemental metal comprising dissolved complex material.

For example, with respect to contacting of the intermediate operative solution with the reagent material in the reaction zone 18, this is effected at room temperature and atmospheric pressure.

In some embodiments, at least a fraction of the product solution component is recovered from the product mixture 112, and is subjected to further treatment to effect recovery of at least one of the at least one product solution component-based target elemental metal comprising dissolved complex material. In this respect, for example, at least a fraction of the product solution component is separated from the product mixture 112 in at least one sold-liquid separation unit operation 20 (for example, the solid-liquid separation unit operation 20 is a mechanical filtration unit operation) to thereby provide a recovered product solution component 116 and also provide tailings 118. The recovered product solution component 116 includes the at least one product solution component-based target elemental metal comprising dissolved complex material. In some embodiments, the recovered product solution component 116 is recycled to the leaching zone 10 and thereby forms at least a fraction of the process feed material 100. In such cases, the respective at least one target elemental metal of each one of the at least one product solution component-based target elemental metal comprising dissolved complex material of the recovered product solution component 116 remains solvated within the leaching zone 10 and is discharged from the leaching zone 10 in the product leachate 120 and is then subjected to further treatment in the target metal recovery unit operation 22 to effect recovery of the one or more target metals.

EXAMPLES

Embodiments of the present invention will be described in further detail with reference to the following non-limitative examples.

Example 1

-   (a) Solubilization of Metalliferrous Material: H₂SO₄/SO₂ Leach

1600 grams wet filter cake (53.4% moisture), the composition of which is specified in Table 1, prepared from a lamellae thickener underflow were combined with 1600 mls of water in a 3.8 liter titanium lined batch autoclave. The autoclave was equipped with a recirculation loop into which sulphur dioxide gas could be injected. The recirculation loop was also equipped with Oxidation-reduction potential (“ORP”) and pH electrodes. The autoclave was also set up so as to allow injection of concentrated sulphuric acid (See FIG. 1).

The autoclave was sealed and the circulation loop was started at a flow rate of approximately 350 mls/min. Sulphur dioxide gas was injected into the recirculation loop at a rate of approximately 275 to 300 mls/min. Sulphuric acid was injected into the autoclave so as to maintain a pH of 1.8. The ORP and pressure in the autoclave were monitored. In a typical reaction, the ORP would decrease from about 400 mV to 40 mV and the pressure in the autoclave would rise to about two (2) psig. The reaction time was in the order of 100 minutes.

The pressure rise was taken as an indication that the reaction was complete and further addition of sulphur dioxide and sulphuric acid were discontinued. The contents of the autoclave were then filtered. At this stage, filtration proceeded significantly faster than the original filtration to produce the cake used in the initial charge.

At this stage, samples of the solids and the solution were collected and submitted for analysis. The assay results are shown in FIG. 2.

-   (b) Contacting of Intermediate Operative Solution with Reagent:     Air/Ammonia Precipitation Of Iron

825 mls of solution from the H₂SO₄/SO₂ leach were then collected and added over a period of 5 minutes to rapidly stirred 675 millilitres of aqueous ammonia solution (164 g/L NH₃). This ensured that there is always an excess of ammonia present in the reactor. Ammoniated air was prepared by passing air through a solution of 110 g/L aqueous ammonia. As the ammonia in the aqueous ammonia depleted it was topped up by the addition of 30 millilitres of concentrated ammonium hydroxide solution every 30 minutes. The ammoniated air was sparged into the blend of H₂SO₄/SO₂ leach solution and the aqueous ammonia solution (see FIG. 3). The air addition was maintained for 5.5 hours during which time the ORP increased from −641 to −30 mV. The provided air effects conversion of ferrous hydroxide to goethite, which is relatively more stable in air and easier to filter than ferrous hydroxide. The typical molar ratio of ammonia to total metals at the end of the process was about 8 and the ammonium sulphate concentration was approximately 88 g/L.

The air was discontinued and the slurry was filtered. The assay results are shown in FIG. 4. As was the case with the residue from the leach step, the product slurry filtered faster than the original slurry from the lamellae thickener underflow.

-   (c) Oxygen/Ammonia Leach of Residue from Reduction Leach

The residue from the first H₂SO₄/SO₂ leach can be fed to a second ammonia leach circuit, thereby effecting recycling of the H₂SO₄/SO₂ leach residue. A leach test was performed on pooled sample of residues from two reduction leaches of lamellae thickener underflow solids. The assays of the feed solids and the leach residues are shown in FIG. 5. Extraction calculations, using an iron tie, show that the majority of the nickel and cobalt are leachable. An XRD analysis of the residue shows that it is primarily quartz and nickel oxide (see FIG. 6). Since it is unlikely that the nickel oxide was formed in either the reduction leach of the ammonia leach there is a strong chance that it originated with the feed into the refinery.

Example 2

This example is illustrative of the fact that the subject method can be easily adapted to changes in the composition of the pre-cursor metalliferrous material source. Changes in the composition of the metalliferrous material source and, therefore, the metalliferrous material, can have an impact on the mass balance of the process. This is because there are two paths by which some of the target elemental metals (eg. nickel and cobalt) can be recovered. If the target elemental metal is sulphidic, then it is not solubilized when the metalliferrous material is leached with the aqueous reductant and, therefore, is recovered by recycling the leach residue to the step which effects leaching of the process feed material (including the metalliferrous material source). If the target elemental metal is oxidic, it is recovered by leaching the metalliferrous material with an aqueous reductant.

Experiments were conducted using the experimental set-up for Example 1, using a metalliferrous material with a relatively low metal sulphide content and a metalliferrous material with a relatively high metal sulphide content. The table in FIG. 13 illustrates that when there are relatively few metal sulphides in the metalliferrous material being leached (as evidenced by an iron content of 33%) there are relatively high recoveries of the target elemental metals through solubilization (see column entitled “Extraction to Reductive Leach Solution”). On the other hand, when the metal sulphide content is relatively high in the metalliferrous material (see the table in FIG. 14), the overall recoveries of the target elemental metals through solubilization drops off substantially (see column entitled “Extraction to Reductive Leach Solution”), but a significant fraction of the target elemental metals in the metalliferrous material report to the residue arising from the leaching of the metalliferrous material. In the experiment with relatively high metal sulphide content metalliferrous material, the concentrations of the nickel and cobalt in the residue from the leaching of the metalliferrous material are, respectively, 29.8% and 5.75%. This indicates that the residue is rich in unleached metal sulphides. The leaching of the residue using ammonia solution effects extraction of the target metal sulphides, as illustrated in the column entitled “Extraction in Ammonia Leach of Residue” in the table of FIG. 14, and contributes to a relatively high overall recovery of the target elemental metals (see column “Overall Recovery”).

The table in FIG. 15 illustrates assays for both the original metalliferrous material feed to the reductive leach process along with the assays of the reductive leach solution and the solution (ie. the “iron precipitation solution”) produced during the step where the reductive leach solution is contacted with the at least one reagent system (to effect iron precipitation) for a metalliferrous material feed with low metal sulphide content.

The assays of the final residue to tailings solids show that overall the solids discharged to tailings are substantially depleted in nickel and cobalt.

In some embodiments, the iron precipitation reaction may be similar enough to that in some existing ammonia leach plants with respect to deportment of impurities that no further processing is required for removal of impurities such as manganese and chromium.

It will be understood, of course, that modifications can be made in the embodiments of the invention described herein without departing from the scope and purview of the invention as defined by the appended claims. 

1. A method of treating a metalliferrous material source comprising: providing a metalliferrous material source, wherein the metalliferrous material source includes at least one metalliferrous material source-based target elemental metal and at least one metalliferrous material source-based non-target elemental metal; providing a process feed material, wherein the process feed material includes the metalliferrous material source, leaching the process feed material in a preliminary leaching zone to effect production of a preliminary leach product including a preliminary leach solution and a preliminary leach solid residue, wherein the preliminary leach solution includes at least one preliminary leach solution-based target elemental metal, and each one of the at least one preliminary leach solution-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal; separating at least a fraction of the preliminary leach solid residue from the preliminary leach product such that a metalliferrous material is provided, wherein the metalliferrous material is includes at least a fraction of the separated preliminary leach solid residue, and wherein the metalliferrous material includes at least one metalliferrous material-based target elemental metal and at least one metalliferrous material-based non-target elemental metal, wherein each one of the at least one metalliferrous material-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal and at least one of the at least one metalliferrous material-based non-target elemental metal is a one of the at least one metalliferrous material source-based non-target elemental metal; leaching the metalliferrous material with an operative leachant to effect production of an intermediate product mixture including an intermediate operative solution product and an intermediate solid residue, wherein the intermediate operative solution product includes at least one dissolved intermediate operative solution product-based target elemental metal, wherein each one of the at least one dissolved intermediate operative solution product-based target elemental metal is a one of the at least one metalliferrous material-based target elemental metal, and wherein the intermediate solid residue includes at least one intermediate solid residue-based target elemental metal comprising solid material, wherein each one of the at least one intermediate solid residue-based target elemental metal comprising solid material includes at least one intermediate solid residue-based target elemental metal, and wherein each one intermediate solid residue-based target elemental metal is a one of the at least one metalliferrous material-based target elemental metal; separating at least a fraction of the intermediate solid residue from the intermediate product mixture to provide a separated intermediate solid residue; and recycling the separated intermediate solid residue to the preliminary leaching zone such that the process feed material includes the recycled intermediate solid residue.
 2. The method as claimed in claim 1, wherein at least one of the at least one dissolved intermediate operative solution product-based target elemental metal is recovered from the intermediate operative solution.
 3. The method as claimed in claim 2, wherein the intermediate operative solution is contacted with a reagent so as to effect production of a product mixture including at least one dissolved reaction product based-target elemental metal comprising material and at least one solid reaction product-based non-target elemental metal comprising material, wherein each one of the at least one dissolved reaction product based-target elemental metal comprising material includes at least one dissolved reaction product based-target elemental metal which is a one of the at least one metalliferrous material-based target elemental metal, and wherein each one of the at least one solid reaction product-based non-target elemental metal comprising material includes at least one solid reaction product-based non-target elemental metal which is a one of the at least one metalliferrous material-based non-target elemental metal; and wherein at least a fraction of the dissolved reaction product based-target elemental metal comprising material is separated from the product mixture.
 4. The method as claimed in claim 3, wherein the at least one metalliferrous material-based target elemental metal includes at least one of nickel and cobalt.
 5. The method as claimed in claim 4, wherein the at least one metalliferrous material-based non-target elemental metal includes iron.
 6. The method as claimed in claim 5, wherein the operative leachant, with which the metalliferrous material is contacted, includes an aqueous solution including dissolved sulphuric acid and dissolved sulphur dioxide.
 7. The method as claimed in claim 5, wherein the reagent, with which the intermediate operative solution is contacted, includes aqueous ammonia.
 8. The method as claimed in claim 7, wherein the metalliferrous material source further includes at least one metalliferrous material source-based target metal sulphide, wherein each one of the at least one metalliferrous material source-based target metal sulphide includes at least one metalliferrous material source target metal sulphide-based target elemental metal, wherein each one of the at least one metalliferrous material source target metal sulphide-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal; and wherein the metalliferrous material further includes at least one metalliferrous material-based target metal sulphide, and each one of the at least one metalliferrous material-based target metal sulphide is a one of the at least metalliferrous material source-based target metal sulphide and includes at least one metalliferrous material target metal sulphide-based target elemental metal which is a one of the at least one metalliferrous material source-based target elemental metal; and wherein the intermediate solid residue, whose production is effected by the leaching of the metalliferrous material with the operative leachant, further includes at least one intermediate solid residue-based target metal sulphide, wherein each one of the at least one intermediate solid residue-based target metal sulphide is a one of the at least one metalliferrous material-based target metal sulphide, and wherein each one of the at least one intermediate solid residue-based target metal sulphide includes at least one intermediate solid residue target metal sulphide-based target elemental metal, and each one of the at least one intermediate solid residue target metal sulphide based-target elemental metal is a one of the at least one metalliferrous material-based target elemental metal.
 9. The method as claimed in claim 8, wherein the leaching of the process feed material is effected by contacting the process feed material with an aqueous solution comprising ammonia and ammonium sulphate.
 10. The method as claimed in claim 8, wherein the at least one intermediate solid residue-based target elemental metal comprising metal sulphide includes at least one of nickel sulphide and cobalt sulphide.
 11. The method as claimed in claim 8, wherein at least one of the at least one dissolved intermediate operative solution-based target elemental metal of the intermediate operative solution is the same target elemental metal as a one of the at least one intermediate solid residue target metal sulphide-based target elemental metal.
 12. The method as claimed in claim 8, wherein at least one of the at least one intermediate solid residue target metal sulphide-based target elemental metal is a one of the at least one dissolved preliminary operative solution-based target elemental metal.
 13. A method of treating a metalliferrous material source, comprising: providing a metalliferrous material source including at least one target elemental metal comprising metalliferrous material source-based metal sulphide and at least one non-target elemental metal comprising metalliferrous material source-based metal sulphide, wherein each one of the at least one target elemental metal comprising metalliferrous material source-based metal sulphide includes at least one metalliferrous material source-based target elemental metal, wherein the at least one target elemental metal comprising metalliferrous material source-based metal sulphide includes at least one of nickel sulphide and cobalt sulphide, such that the at least one metalliferrous material source-based target elemental metal includes at least one of nickel and cobalt, and wherein each one of the at least one non-target elemental metal comprising metalliferrous material source-based metal sulphide includes at least one metalliferrous material source-based non-target elemental metal, and wherein the at least one non-target elemental metal comprising metalliferrous material source-based metal sulphide includes iron sulphide, such that the at least one metalliferrous material source-based non-target elemental metal includes iron; providing a process feed material, wherein the process feed material includes the metalliferrous material source, leaching the process feed material in a preliminary leaching zone with a preliminary leachant to effect production of a preliminary leach product including a preliminary leach solution and a preliminary leach solid residue, wherein the preliminary leach solution includes at least one preliminary leach solution-based target elemental metal, wherein each one of the at least one preliminary leach solution-based target elemental metal is a one of the at least one metalliferrous material source-based target elemental metal, and wherein the preliminary leach solid residue includes: (i) at least one of nickel sulphide and cobalt sulphide, (ii) at least one of other nickel comprising material and other cobalt comprising material, and (iii) iron comprising material, and wherein the preliminary leachant is an aqueous solution comprising ammonia and ammonium sulphate; separating at least a fraction of the preliminary leach solid residue from the preliminary leach product such that a metalliferrous material is provided, wherein the metalliferrous material includes at least a fraction of the separated preliminary leach solid residue; leaching at least a fraction of the metalliferrous material with an aqueous solution including dissolved sulphuric acid and dissolved sulphur dioxide in a leaching zone so as to effect production of an operative leach product including a leachate component and a solid residue component, wherein the leachate component includes nickel sulphate, cobalt sulphate, and iron sulphate, and wherein the solid residue component includes at least one of nickel sulphide and cobalt sulphide; separating at least a fraction of the solid residue component from the operative leach product to provide a recovered solid residue component; and recycling the recovered solid residue component to the preliminary leaching zone.
 14. A method of treating a metalliferrous material source, comprising: providing a metalliferrous material source including at least one of nickel sulphide and cobalt sulphide, and also including iron sulphide; leaching the metalliferrous material source with a preliminary leachant in a leaching zone to effect production of a preliminary leach product including a preliminary leach solution and a preliminary leach solid residue, wherein the preliminary leachant includes an aqueous solution comprising ammonia and ammonium sulphate, and wherein the preliminary leach solution includes at least one of dissolved nickel comprising material and dissolved cobalt comprising material, and wherein the preliminary leach solid residue includes: (i) at least one of nickel sulphide and cobalt sulphide, (ii) at least one of other nickel comprising material and other cobalt comprising material, and (iii) other iron comprising material; separating at least a fraction of the preliminary leach solid residue from the preliminary leach product such that a metalliferrous material is provided, wherein the metalliferrous material includes at least a fraction of the separated preliminary leach solid residue; leaching at least a fraction of the metalliferrous material with an aqueous solution including dissolved sulphuric acid and dissolved sulphur dioxide in a leaching zone so as to effect production of an operative leach product including a leachate component and a solid residue component, wherein the leachate component includes nickel sulphate, cobalt sulphate, and iron sulphate, and wherein the solid residue component includes at least one of nickel sulphide and cobalt sulphide; separating at least a fraction of the solid residue component from the operative leach product to provide a recovered solid residue component; and recycling the recovered solid residue component to the preliminary leaching zone.
 15. The method as claimed in claim 6, wherein the reagent, with which the intermediate operative solution is contacted, includes aqueous ammonia. 